Windows 7 ignoring DHCP Offer packets

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My laptop with Windows 7 can't renew it's IP address via DHCP. I've tried both my ethernet card and my WIFI card, and I got nothing. It stats fine when I log in in my session after a reboot, but after that, I cant renew. It works fine with a static address configured, but it's useless since I move a lot between networks.

I've captured DHCP traffic in my NIC and I can see the DHCP Offer packets reaching my laptop. But Windows won't use it. I turned on the DHCP Debug in Windows, and it informs me that the DHCP Discover packets are being sent out, but it doesn't see any Offer packet. It shows a message about timeout. I don't know what I've disabled to get this behavior.

I tried with a Live CD with Ubuntu, and the DHCP works fine. So I presume that the problem is some configuration in my Windows settings. But I don't know where.

Please help!

ujemvi

Posted 2015-08-07T19:47:24.923

Reputation: 31

Did you check if DHCP Service is running in your computer ? – pun – 2015-08-07T19:53:02.867

I've been restating a service named "DHCP Client", I presume that's the one you're saying. – ujemvi – 2015-08-07T19:56:17.357

try start>run>cmd type the following comand and press enter [net start dhcp] – Francisco Tapia – 2015-08-07T20:52:26.707

Answers

0

I have a similar issue. Try the above fix, in short: create or edit the following registry key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{GUID}\DhcpConnForceBroadcastFlag

The key should be set to 1 (0 for unicast, 1 for broadcast).

then create or edit the following 32bit DWORD:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{GUID}\DhcpConnEnableBcastFlagToggle

and set it to 0.

All credit goes to this link:

http://sysadministrivia.blogspot.com.au/2011/04/dhcp-broadcast-flag-problem-with-dhcp.html

note on a windows 7 PC I had to do the exact opposite.

DhcpConnForceBroadcastFlag = 0 DhcpConnEnableBcastFlagToggle = 1

Jacob Jarick

Posted 2015-08-07T19:47:24.923

Reputation: 3